Add Person wizard should support continue by hiting the enter key

[saemideluxe]

Because the wizard has some pages which do only have a select element (and no <input> elements) the default browser behaviour of using enter to send the form does not work. I think we need to add that bahaviour with javascript for this wizard.

[saemideluxe]

But be carefull on the last page where we have a field to enter the address. I should still be possible to enter multiple lines for an address.

[dward2nd]

Done in #192

[saemideluxe]

Needs to be released.